What are the management protocols for Diabetic Ketoacidosis (DKA) and Hyperosmolar Hyperglycemic State (HHS)?

Management Protocols for DKA and HHS

Initial Diagnostic Criteria

DKA is diagnosed by blood glucose >250 mg/dL, arterial pH <7.3, bicarbonate <15 mEq/L, and moderate ketonuria or ketonemia, while HHS requires blood glucose >600 mg/dL, arterial pH >7.3, bicarbonate >15 mEq/L, effective serum osmolality >320 mOsm/kg, and only small ketones. 1

Immediate Laboratory Assessment

• Obtain arterial blood gases, complete blood count with differential, urinalysis, blood glucose, BUN, electrolytes, chemistry profile, creatinine, and electrocardiogram immediately 1
• Calculate effective serum osmolality: 2[measured Na (mEq/L)] + glucose (mg/dL)/18 2, 3
• Correct serum sodium for hyperglycemia by adding 1.6 mEq to sodium value for each 100 mg/dL glucose above 100 mg/dL 1
• Obtain chest X-ray and cultures (blood, urine, throat) if infection is suspected as the precipitating cause 1

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Fluid Resuscitation Protocol

First Hour (0-60 minutes)

Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/h (1-1.5 L in average adult) during the first hour to expand intravascular volume and restore renal perfusion in both DKA and HHS. 1, 2

• In pediatric patients (<20 years), use 0.9% NaCl at 10-20 mL/kg/h to minimize cerebral edema risk, not exceeding 50 mL/kg over the first 4 hours 1

Subsequent Fluid Management (After First Hour)

• If corrected serum sodium is normal or elevated: switch to 0.45% NaCl at 4-14 mL/kg/h 1
• If corrected serum sodium is low: continue 0.9% NaCl at 4-14 mL/kg/h 1
• Target fluid replacement to correct estimated deficits within 24 hours 1, 2
• Critical safety parameter: induced change in serum osmolality must not exceed 3 mOsm/kg/h to prevent cerebral edema and central pontine myelinolysis 1, 2, 4

Typical Fluid Deficits

• DKA: 6 L total water deficit (100 mL/kg) 1
• HHS: 9 L total water deficit (100-200 mL/kg) 1

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Insulin Therapy Protocol

DKA Insulin Management

Start continuous IV regular insulin infusion at 0.1 units/kg/h (typically 5-10 units/hour) after initial fluid resuscitation and after confirming potassium >3.3 mEq/L. 2, 3

• If glucose does not fall by 50 mg/dL in the first hour, double the insulin infusion rate hourly until steady decline of 50-75 mg/dL/h is achieved 3
• When plasma glucose reaches 250 mg/dL in DKA, decrease insulin to 0.05-0.1 units/kg/h (3-6 units/h) 3
• Add 5-10% dextrose to IV fluids when glucose falls below 250 mg/dL in DKA to prevent hypoglycemia while continuing to clear ketones 2

HHS Insulin Management

In HHS, withhold insulin until blood glucose stops falling with IV fluids alone, unless significant ketonemia is present. 4, 5

• This critical distinction exists because fluid replacement alone causes substantial glucose decline in HHS, and premature insulin use may precipitate complications 5
• Once insulin is started in HHS, use 0.1 units/kg/h continuous IV infusion 2
• When plasma glucose reaches 300 mg/dL in HHS, decrease insulin to 0.05-0.1 units/kg/h 2, 3
• Add 5-10% dextrose when glucose falls below 300 mg/dL in HHS 2, 3
• Continue insulin until mental obtundation and hyperosmolarity resolve 3

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Potassium Replacement Protocol

Once renal function is assured (urine output present), add 20-30 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4) regardless of initial potassium level, as insulin therapy will drive potassium intracellularly. 1

Critical Safety Rule

• Never start insulin if serum potassium <3.3 mEq/L - this can cause fatal cardiac arrhythmias 3, 6
• If initial potassium <3.3 mEq/L, give potassium replacement first before starting insulin 3
• Monitor potassium levels every 2-4 hours during initial treatment 2, 3

Typical Electrolyte Deficits

• Potassium deficit in DKA: 3-5 mEq/kg 1
• Potassium deficit in HHS: 5-15 mEq/kg 1
• Phosphate deficit: 3-7 mmol/kg 1
• Magnesium deficit: 1-2 mEq/kg 1

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Monitoring Protocol

Hourly Monitoring

• Vital signs, mental status, fluid input/output, and hemodynamic parameters 2
• Blood glucose every 1-2 hours until stable 2

Every 2-4 Hours

• Serum electrolytes (sodium, potassium, chloride, bicarbonate) 2, 3
• Calculate effective serum osmolality to guide fluid management 2, 3
• BUN, creatinine 3

Monitoring for Complications

• Cerebral edema (especially in pediatric patients and with rapid osmolality correction) 2, 4
• Hypokalemia and cardiac arrhythmias 6
• Fluid overload in elderly or those with cardiac/renal compromise 1, 2
• Vascular thrombosis, myocardial infarction, stroke 2, 5

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Transition to Subcutaneous Insulin

Administer basal subcutaneous insulin 2-4 hours before discontinuing IV insulin to prevent rebound hyperglycemia. 2, 3

Common Pitfall to Avoid

The most frequent management error is premature termination of IV insulin or insufficient timing/dosing of subcutaneous insulin before stopping the IV infusion 7. This leads to recurrent hyperglycemia and prolonged hospital stays.

Resolution Criteria for DKA

• Blood glucose <200 mg/dL 1
• Anion gap ≤12 mEq/L 1
• Serum bicarbonate ≥15 mEq/L 1
• Venous pH >7.3 1

Resolution Criteria for HHS

• Osmolality <300 mOsm/kg 4
• Hypovolemia corrected (urine output ≥0.5 mL/kg/h) 4
• Cognitive status returned to baseline 4
• Blood glucose <15 mmol/L (270 mg/dL) 4

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Key Differences Between DKA and HHS Management

The fundamental distinction is that DKA requires immediate insulin therapy as the cornerstone of treatment, while HHS requires fluid replacement as the primary intervention with delayed insulin administration. 8, 5

• DKA develops over hours with prominent ketoacidosis; HHS develops over days with extreme dehydration 5
• In HHS, fluid replacement alone causes significant glucose decline, making premature insulin potentially harmful 5
• HHS has higher mortality than DKA and greater risk of thrombotic complications 4, 5
• Mixed DKA/HHS presentations occur in up to one-third of cases and should be managed based on the most prominent clinical features 8

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Special Populations and Precautions

Elderly and Cardiac/Renal Compromise

• Use more cautious fluid rates with closer hemodynamic monitoring 2
• Avoid excessive fluid administration to prevent iatrogenic fluid overload 1, 2

Pediatric Considerations

• Limit initial fluid resuscitation to minimize cerebral edema risk 1
• Avoid rapid correction of hyperosmolarity in mixed cases 8

Bicarbonate Therapy

Do not use bicarbonate therapy routinely - it has not been shown to improve outcomes and may worsen hypokalemia. 2, 6